Inhalation device

ABSTRACT

The invention relates to an inhalation device by which powdered material can be inhaled. A plurality of powder containers, each having a powder containing depression therein, may be individually fed to a use station which cooperates with an inhalation means. The inhalation means includes an outlet communicating with the open container by a passage, which passage has a wall means which cooperates with the powder containing depression to define a venturi.

BACKGROUND OF THE INVENTION

This invention relates to an inhalation device for use in the inhalationof material in powder form. More particularly, it relates to a device bymeans of which medicament in powder form can be inhaled, and it is sodescribed below.

SUMMARY OF THE INVENTION

According to the present invention there is provided an inhalationdevice by means of which material in powder form can be inhaled,comprising means holding a powder container having a powder-containingdepression therein at a use station, and inhalation means for enablingthe powder to be inhaled from a container at the use station, saidinhalation means comprising an outlet communicating with the opencontainer by a passage, said passage comprising wall means whichcooperate with the said depression to define a venturi.

The use of a venturi is advantageous in that it provides for rapid andsubstantially complete emptying of the container.

The invention further provides for the use of such an inhalation meansin an inhalation device by means of which material in powder form can beinhaled, comprising means for holding a stack of unused powdercontainers and storage means for receiving each used container from theuse station after the powder has been inhaled therefrom and collectingthe containers therein.

The invention can also be used with other types of inhalation means suchas in an inhalation device as described in GB-A-2242134 in which atleast one powder container is defined between two members peelablysecured to one another, the device comprising means defining an openingstation for the said at least one container, and means for peeling themembers apart at the opening station to open the container.

The invention additionally can be used with an inhalation device asdescribed in WO 92/00771 in which there is provided a storage chamberfor the powder to be inhaled and a metering member which is intended toprovide at least one dispensing cup defining the at least one powdercontainer, the said metering member being moveable between a firstposition in which a container is presented to the storage chamber toreceive a dose of the powder to be inhaled and a second position definedby the use station.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is further described below with reference to theaccompanying drawings, in which:

FIG. 1 is a side view, in section, showing diagrammatically a firstembodiment of the present invention;

FIG. 2 is an underplan view of the upper portion of the embodiment shownin FIG. 1, on a larger scale;

FIG. 3 is a sectional view generally taken along line III--III in FIG.2, but showing only slider and container component of FIG. 2;

FIG. 4 is a perspective view of a device embodying the principles ofFIGS. 1 to 3;

FIG. 4a is a view from above showing part of the device of FIG. 4;

FIG. 4b is a vertical section through part of the device of FIG. 4,showing in more detail the design of the mouthpiece thereof;

FIG. 5 shows a single powder container;

FIGS. 6a and 6b show a body and slider mechanism of part of anembodiment employing a rotary slider, with FIG. 6a being a section online 6a--6a in FIG. 6b; and

FIGS. 7a and 7b, and 8a and 8b are views corresponding to FIGS. 6a and6b, with the components in other positions;

FIG. 9 is a longitudinal section, with portions cut away, showing afurther embodiment;

FIG. 9a shows a cut-away detail at the top of the stack of containers ofthe embodiment of FIG. 9;

FIGS. 10a and 10b show, diagrammatically and in section, the upperportion of the embodiment of FIGS. 9 and 9a in its inoperative andoperative positions, respectively;

FIG. 11 is a section through the stack of unused containers shown inFIG. 10b, taken at right angles thereto, along with a mouthpiece; and

FIG. 12 is a schematic longitudinal section through another embodiment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In the embodiment shown in FIGS. 1 to 4, a body 201 is provided withinwhich is formed a generally U-shaped passage 202. This passage comprisesa first straight portion 203 which contains a stack 204 of unused, i.e.powder-containing, powder containers 205, and a second straight portion206 which contains a stack 207 of used, i.e. empty, powder containers.At the lower end of the stack 204 is a piston 208, and at the lower endof the stack 207 is a piston 209. A coil spring 210 is located, in astate of compression, within the U-shaped passage 202, with one end ofthe spring bearing against the piston 208 and the other end of thespring bearing against the piston 209. The spring 210 has end portions210a and 210b in which adjacent turns of the spring are spaced somewhatfrom one another, whilst over the rest of the length of the spring thecoils are located tightly against one another. The effect of this isthat the spring 210 provides a flexible member of substantially constantlength, with a substantially constant spring force being generated onlyby the end portions 210a and 210b.

It should be mentioned at this point that other forms of spring can beused instead. Thus, for example, a simple compression spring, with theturns equally spaced apart over its whole length, could be used,However, to achieve the same compression stiffness as the spring 210described, this would need to be made of relatively thick wire, andwould therefore be less able to bend in the curved portion of theU-shaped passage. Another possibility is to use a flexible flat strip ofmetal or a plastics material, with a short compression spring at eachend thereof. This has the advantage that the flat strip can be madehighly flexible, and can therefore bend round a tighter radius than aconventional circular cross-section spring. However, it has thedisadvantages that it involves additional components, and, in the caseof a plastics strip, the material may creep with time. Yet anotherpossibility is to use a flat strip formed into integral `Z` springs ateach end. This provides a highly flexible spring, whilst avoiding theneed for more than one component, although the spring needs to becarefully designed to achieve an adequate load. Metal is preferred as amaterial for the strip, since a plastics strip would be liable to creep.

A cover 211 is secured to the top of the body 201, and has a recess 212,which is rectangular both in vertical section and plan view on theunderside thereof. A slider 213 is slidably mounted in the recess 212.The cover 211 has an air inlet passage 214 and an outlet passage 215 forair and powder. In practice, the passage 215 is connected to amouthpiece or nosepiece for inhalation, though this is not shown inFIG. 1. The slider 213 has a passage 216 which opens into the lower faceof the slider 213. When the slider 213 is in its left hand position (itis shown in an intermediate position in FIG. 1) the opening in thepassage 216 communicates with the upper end of the stack 204 and theends of the passage 216 communicate respectively with the passages 214and 215. Thus, when the slider 213 is in the left hand position,inhalation by the user through the mouthpiece or nosepiece attached topassage 215 causes air to flow in through passage 214 and thence throughpassage 216, entraining powder from the topmost of the containers 205 inthe stack 204, and thence, with the powder entrained therein, outthrough the passage 215. Each of the containers 205 has a depression inits upper surface to hold the powder, and the shape of this depressionis preferably such that it forms a smooth continuation with the adjacentwall of the passage 216, thereby to improve the efficiency with whichpowder is scoured from the depression by the air flow. The combinationof the passages 214, 215 and 216, and the depression in the container205 forms a venturi, as can be seen in FIG. 1.

The slider 213 operates to transfer each powder container, as it isused, from the top of stack 204 to the top of stack 207. The slider canbe seen in more detail in FIGS. 2 and 3. It will be seen there that ithas a recess 217 on the underside thereof, the recess being defined by ashoulder 218 at one end and a ramp 219 at the other end. As the slider213 moves from left to right, (as viewed in all of FIGS. 1 to 3), theshoulder 218 engages the left hand edge of the container 205 which is atthe top of the stack 204. The slider moves this container onto the topof the existing stack 207 of used containers. The leading lower edgeportion 220 of the slider 213 stays in contact with the top of theexisting stack 207 until after the leading edge of the new usedcontainer 205 is over the edge of the stack 207. This ensures that thenew used container is free to assume its desired position on the top ofthe existing stack.

When the slider 213 is then moved leftwards, the stack 207 isprogressively compressed as the right hand edge of the top container inthe stack is engaged by the ramp 219, until the leading edge portion 220is over the top of the stack 207. During this leftward motion of theslider 213 the top container in the stack 207 is prevented from movingleftwardly by a non-return catch which is provided by a pair of pins221. The pins pass through apertures 223 in the cover 211 and are biasedtowards one another, and in FIG. 2 this is shown as being achieved byflexible resilient members 222. However, any suitable alternativebiasing means could be used instead. The inner ends of the pins 221 arebevelled so that although they prevent the slider carrying containersfrom right to left they do not prevent the slider carrying containersfrom left to right.

One of the containers 205, with its depression 205a, is shown on alarger scale in FIG. 5, and it can be seen to be generally rectangularin plan, but with two opposite bevelled edges (not labeled). It will beappreciated that these are convenient from the point of view of theoperation of the non-return catch in FIG. 2.

The slider 213 may be moved back and forth, for example, by a lever 224,part of which is indicated in broken lines in FIG. 3. The lever ispivotally mounted on the body 201 by a shaft 225, which passes through abore 226 indicated in FIG. 1. The lever itself is not shown in FIG. 1.The lever has an arcuate slot 227 which receives the end of a pin 228which is fixedly secured in the slider 213. The lever 224 is shownmoving clockwise, so as to carry the pin 228, and hence the slider 213,rightwardly.

The use of a pin and slot provides lost motion between the lever 224 andthe slider 213. In an actual inhalation device this lost motion can beused as movement in which a cap closing the device is moved from aclosed to an open position. Thus, in practice, the lever 224 could beconstituted by the cap itself, with the initial part of the cap openingmovement having no effect on the slider 213, and the final part of thecap opening movement serving to bring the last used container 205 fromthe stack 204 to the stack 207, and thus expose a fresh container at thetop of stack 204 for use. An example of this is shown in FIGS. 4, 4a and4b. This comprises a body 231 with a U-shaped passage 232, a compressionspring 232a and a slider 233. The device is closed by a pivotallymounted mouthpiece cap 234 which provides the lever to move the slider233 aside, against the resilient force of the spring. The cap 234 ispivotally mounted on the body 231 by shafts 237, and has arcuate slots238 in which pins 239 engage, the pins 239 being attached to the slider.

The device has a mouthpiece 235. The mouthpiece 235 is hollow and haswithin it a venturi passage 240. The passage 240 has an air inlet 241which air reaches preferably via an aperture 242 in the mouthpiece. Theaperture 242 is sealed when the cap 234 is in its closed position, asillustrated in FIG. 4b. The slider 213 and a container 205 definetogether part of the wall of the venturi passage.

The principle of operation of the slider is substantially the same as inFIGS. 1 to 3, except that the pins 221 and resilient members 222 arereplaced by a single U-shaped spring 236. As shown in FIG. 4a, thecontainers 205 are modified in that they are provided with cutouts 205b,and the ends of spring 236 engage in the cutouts of the used containersin stack 207. As each container moves from stack 204 to stack 207, itforces the ends of spring 236 apart.

The devices shown in FIGS. 1 to 3 and FIG. 4 employ a linearly movingslider. In an alternative device the slider is moved arcuately by apivotally mounted member, and this is shown in FIGS. 6a, 6b, 7a, 7b, 8aand 8b.

In the embodiment of FIGS. 6 to 8, the "slider" is constituted by aportion of the mouthpiece adjacent the body within which the stacks ofpowder containers are held. In these figures the body is denoted byreference 250, the mouthpiece by reference 251, the stack of unusedcontainers by reference 252 and the stack of used containers byreference 253.

The mouthpiece 251 and body 250 are rotatable relative to one anotherthrough an angle of 90° about an axis which is the longitudinal axis ofthe device, i.e. an axis which is perpendicular to the plane of thepaper in FIGS. 6b, 7b and 8b. The description will be given on the basisthat the body is fixed and the mouthpiece rotates, but it will beunderstood that all that matters is the relative rotation between thesetwo components. Rotation is limited to 90° by means of a stud 259 whichis formed on the upper surface of the body 250 and which runs in anarcuate track 260 formed in the lower portion of the mouthpiece 251.This 90° rotation correlates with the fact that the stack 252 and thestack 253 are disposed at 90° with respect to one another about the axisof rotation of the mouthpiece. It must be understood, however, that thestacks could be at other angles with respect to one another, in whichcase the angle of rotation would be correspondingly different.

In the position shown in FIGS. 6a and 6b, the container at the top ofthe full stack 252 sits in a cutout 254 on the underside of themouthpiece. This cannot be seen in FIGS. 6a and 6b, but is visible inFIG. 7a. The cup at the top of the empty stack 253 is held down by aportion of an inclined ramp 255, also formed on the lower portion of themouthpiece 251. The cup at the top of the empty stack 253 is held inline with the rest of the stack by a resilient non-return catch 256formed on the top of the body 250.

To index the device into a position in which it can be used, themouthpiece 251 is rotated counter-clockwise with respect to the body250, as viewed in FIGS. 6b, 7b and 8b. This is indicated by arrows ineach of the FIGS. 7b and 8b. At the start of this indexing process, thecontainer at the top of the stack 252 is an empty container, this beingthe container from which the user last inhaled. As indicated in FIGS. 7aand 7b, this container, denoted there by reference 257, starts to moveover the top of the stack 253 of empty containers, holding what waspreviously the top container of the stack 253 down while the ramp 255moves away from the stack 253.

When transfer of the container 257 is complete, the catch 256 risesbehind that container, as shown in FIG. 8b. The venturi 258 in themouthpiece is now in position over a full container at the top of thestack 252, and the device is in its primed position, ready forinhalation.

After the user has inhaled the powder from the top container, themouthpiece is rotated clockwise through 90° to bring the device back tothe position shown in FIGS. 6a and 6b. During this clockwise rotationthe transferred container 257 is forced down into the stack 253 of emptycontainers by the ramp 255, and the catch 256 prevents the container 257being drawn back towards the stack 252. When the 90° clockwise rotationhas been completed, the newly emptied container on top of stack 252snaps up into the cutout 254 in the mouthpiece 251, ready for the nextoperation.

FIGS. 9, 9a, 10a, 10b and 11 show a further embodiment in which, likethe embodiments of FIGS. 1 to 8, there is a U-shaped passage containinga stack of unused containers and a stack of used containers. As in thecase of the embodiments of FIGS. 1 to 4, containers are shifted from thetop of one stack to the top of the other stack by a translationalmovement.

The device comprises a body 300 in which there is an outlet spout in theform of a mouthpiece 302. It would alternatively be possible for thedevice to be adapted for nasal use instead of oral use, in which case anasal outlet would replace the mouthpiece. The same is true of the otherembodiments described herein. The outlet end of the mouthpiece is closedby a cap 304 which is pivotally mounted on the body by means of a pivot306 for pivotal movement with respect thereto. The powder containers areheld in two stacks within a cartridge 307. Initially, all the containersare in a stack 308, which consists of a number of unused (i.e. full)containers surmounted by one empty container which acts as an initiallid to dose off the top of the stack. The "top" for this purpose is theend of the stack nearer the mouthpiece 302. A stack of used (i.e. empty)containers is formed during operation of the device in the chamberindicated by reference numeral 310. A window 311 is provided in the body300, through which the stack of empty containers can be viewed whenthere are sufficient containers therein to fill the chamber 310 almostcompletely. This gives warning to the user when the full containers havealmost all been used.

The end of the stack 308 remote from the mouthpiece 302 is seated on aspring member 312 which comprises a top member 314, a base member 316and a compression spring 318 which urges the members 314 and 316 awayfrom one another. One end of a U-shaped pusher member 320 bears againstthe base member 316. The pusher member 320 passes round a guide surface322, over which it can slide, and the other end thereof bears against apad 324 which can be seen in FIG. 9a and which is slidable in thechamber 310. The pusher 320 is in the form of a flexible plate, forexample of a plastics material. The guide surface 322 is formed on oneend of a rod 326, the other end of which, as can be seen in FIG. 9a,provides a surface against which one end of a compression spring 328 canbear. The other end of the spring 328 bears against the end of a blade330, the purpose of which is described below.

The shaft 306, which provides pivotal movement between the cap 304 andthe body 300, carries a crank arm 332. Preferably, there is a pair ofcrank arms, one at each end of the shaft 306, only one of these armsbeing visible in FIG. 9. The crank arm 302 and shaft 306 rotate with thecap 304, and thus with respect to the body 300.

Beneath the inner end of the mouthpiece 302, which is defined by a plate334, there is mounted a slider 336 which is movable transversely withrespect to the longitudinal axis of the mouthpiece 302, i.e. in adirection which is upward and downward as viewed in FIG. 9. The sliderhas a lug 338 which is engaged by the end of the crank arm 332 after thearm has rotated clockwise from its illustrated position through an angleof about 45°. If a second crank arm 332 is provided there is acorresponding second lug 338 for it to engage. The slider also defines abearing surface 340 with which a curved surface on the crank arm 332 canengage. The purpose of this is described below in connection with theoperation of the device. It can further be seen in FIG. 9 that theslider has a bead 342 on one end thereof. The end of a safety catch 344operable by a button 346 engages behind the bead 342, and is urged intothe engaging position by a compression spring 348. So long as the catch344 engages behind the bead 342 the slider 336 cannot move.

As already mentioned, at the start there is a complete stack 308consisting entirely of unused containers except for that nearest themouthpiece. The chamber 310 is empty. To use the device the user exertsa force on the button 346 to urge the catch out of engagement behind thebead 342, against the force of the spring 348. While still holding thebutton in that position the user pivots the cap 304 to uncover themouthpiece 302. The first 45° of this pivotal movement has no effect onthe operation of the device, thus allowing for example the sort ofmovement which might be made by someone, particularly a child, playingwith it, without actually moving the slider. Further angular movementbeyond the initial 45° causes the crank arm 332 to engage the lug 338and, provided the safety catch 344 is still out of engagement with thebead 342, the slider 336 is caused to move laterally. The resistance ofthe device to accidental operation is enhanced by the fact that lateralmovement cannot take place, however, unless the user is at that point intime holding down the button 346.

At the start of this movement the empty container at the top of thestack 308 is in a recess 350 on the underside of the slider 336 (seeFIG. 10a). The lateral movement of the slider 336 transfers the emptycontainer at the top of the stack 308 past the blade 330, which isdepressed against the force of the spring 328, so that the emptycontainer is on the end of the pad 324. The pad is thereby depressed,and movement of the pad is transmitted by the pusher 320 to the springmember 312. At this point the spring top member 314 cannot move anyfurther, so the result is that the compression spring 316 is compressedby an amount equal to the thickness of one container. The emptycontainer which is now bearing against the pad 324 forms the start ofthe stack of used containers.

The above described movement of the empty container brings a fullcontainer into alignment with an opening 352 in the underside of theslider. A pair of passages 354, 356 with which the opening 352communicates are in alignment respectively with an aperture whichcommunicates with the interior of the mouthpiece 302 and an aperture 358in the plate 334 through which air can enter from the exterior of thedevice 336 (see FIG. 11). Accordingly, when the user now inhales throughthe mouthpiece, air flows in through the aperture 358 and passage 356,entrains powder from the container, and flows out through the passage354 into the mouthpiece and thence to the patient. As can be seen inFIG. 11, the aperture 358, the passages 354 and 356, and the interior ofthe mouthpiece 302, define, together with the depression in theuppermost powder container, a structure which constitutes a venturi.

When the cap 304 is rotated back to its closed position, the curvedsurface on the rear of the crank arm 332 engages the surface 340 on theslider 336, and forces the slider back to its original position. Duringthis movement the blade 330 prevents the empty container from movingback to the top of the stack 308. The device is now ready for the userto repeat the operation just described. The embodiments just describedare devices which are intended to be thrown away after all thecontainers have been used. Alternatively, however, the device couldcomprise a replaceable cartridge having the stacks of unused and usedcontainers therein, with the cartridge being replaced once all thecontainers had been used. The cartridge could include all or part of aslider mechanism for transferring containers from one stack to theother.

FIG. 12 shows part of a device comprising a mouthpiece 400 having a mainair inlet, passage 402, an air outlet passage 404, and auxiliary airinlets 406 which communicate with the air outlet passage intermediateits ends. The inlet passage 404 diverges as viewed from its upstream endto its downstream end. The mouthpiece has a pair of shoulders 408 formedtherein which define the sides of a track 410, the track runningperpendicular to the plane of the paper in FIG. 12.

The device is intended to handle a medicament pack in which a pluralityof powder containers are defined between an elongate base sheet formedwith longitudinally spaced blisters and a cover sheet hermeticallysealed thereto. FIG. 12 shows one of the blisters, labelled 412 readyfor use, with the portion of the base sheet (not shown) which wouldnormally cover it, peeled away. The blister is positioned so that oneedge region is opposite the downstream end of the main air inlet passage402 and the opposite edge region is opposite the upstream end of the airoutlet passage 404. The main air inlet passage, the interior of theblister, and the air outlet passage form between them what is, in effecta venturi. When the user inhales through the mouthpiece, the air flowthrough the venturi efficiently entrains the powder which is in theblister. Air entering through the auxiliary air inlet 406 ensures thatthe resistance to flow experienced by the user is not unacceptably high.To bring the next blister into position for use, the medicament pack ispulled along the track 410.

I claim:
 1. An inhalation device for use in inhaling material in powderform comprising:means for holding a powder container having a powdercontaining depression at a use station within said inhalation device;and inhalation means for enabling the powder to be inhaled from thepowder container at the use station, said inhalation means comprising anoutlet communicating with the powder container by a passage, saidpassage including wall means leading smoothly into said depressionwherein said wall means and said depression collectively complete acurved section of said passage to define a venturi.
 2. A deviceaccording to claim 1, further comprising means for storing at least oneunused powder container and means for feeding said at least one unusedpowder container to the use station.
 3. A device according to claim 2,further comprising means for retaining a stack of used powdercontainers, and means for delivering each used powder container from theuse station after the powder has been inhaled therefrom to saidretaining means.
 4. A device for use in inhaling material in powder formcomprising:a body portion, at least one container located in said bodyportion, said at least one container including a depression adapted tocontain powder to be inhaled; a member attached to said body portion anddefining an inhalation outlet through which powder contained in thedepression of said at least one container is adapted to be inhaled, saidinhalation outlet being in fluid communication with an inhalationpassage leading from the inhalation outlet to said at least onecontainer, said inhalation passage leading smoothly into the depressionsuch that the depression completes a curved section of the inhalationpassage at which a venturi is formed.
 5. The device according to claim4, including a plurality of containers wherein said body portioncomprises a first storage chamber for housing unused powder containersand a second storage chamber for housing used powder containers.
 6. Thedevice according to claim 5, wherein said first and second chambers areinterconnected and defined by a generally U-shaped passage formed insaid body portion.
 7. The device according to claim 6, furthercomprising means, located in said first and second chambers, for biasingboth the unused and used powder containers toward said member.
 8. Thedevice according to claim 7, wherein said biasing means consists of acoil spring.
 9. The device according to claim 5, wherein said member ismovable between a first position wherein said inhalation passage opensinto said first storage chamber and a second position wherein saidinhalation passage is closed off from said first storage chamber. 10.The device according to claim 9, wherein said member further comprisesmeans for transferring said at least one container from said firststorage chamber to said second storage chamber as said member is movedbetween said first and second storage positions.
 11. The deviceaccording to claim 10, wherein said member is slidably attached to saidbody portion for movement between said first and second positions. 12.The device according to claim 10, wherein said member is rotatablyattached to said body portion for movement between said first and secondpositions.
 13. The device according to claim 4, further comprising a capattached to said body for movement between a first position wherein saidinhalation outlet is covered by said cap and a second position whereinsaid inhalation outlet is exposed.